CiviCRM is a web-based, open source, Constituent Relationship Management (CRM) software geared toward meeting the needs of non-profit and other civic-sector organizations.
A walk threw for a full CiviCRM install on wordpress..
PHP 5.3.x (or newer)
MySQL 5.2+ with INNODB enabled
Download Link:/ http://sourceforge.net/projects/civicrm/files/civicrm-stable/4.2.7/